Endocrinological effects of high-dose Hypericum perforatum extract WS 5570 in healthy subjects

In this single-blind study, the effects of acute oral
administration of high-dose Hypericum perforatum extract WS 5570 on
the cortisol ( COR), adrenocorticotropic hormone ( ACTH), growth
hormone (GH), and prolactin (PRL) secretions were examined in 12
healthy male volunteers. In a randomized order, the subjects
received placebo or WS 5570 at several dosages (600, 900, and 1,200
mg) at 08.00 h on 4 different days. After insertion of an
intravenous catheter, blood samples were drawn 1 h prior to
administration of placebo or WS 5570 ( 600, 900, or 1,200 mg), at
the time of administration, and during 5 h thereafter at intervals
of 30 min. The serum concentrations of COR, GH, and PRL as well as
the plasma levels of ACTH were determined in each blood sample by
means of double antibody radioimmunoassay, fluoroimmunoassay, and
chemiluminescence immunometric assay methods. The area under the
curve value was used as parameter for COR, ACTH, GH, and PRL
responses. Repeated-measures Anova revealed a significant
stimulatory effect of WS 5570 on the ACTH secretion, whereas COR
and PRL secretions were not significantly influenced. Moreover,
there was a stimulatory peak of GH release 240 min after challenge
with WS 5570 in some but not all volunteers, without reaching
statistical significance in comparison with placebo. Mean arterial
blood pressure and heart rate remained unchanged after
administration of WS 5570. Apparently, WS 5570 at the dosages given
in this study inconsistently causes endocrinological effects in
healthy subjects by influencing central neurotransmitters.
Copyright (C) 2004 S. Karger AG, Basel.